private async Task <IReadOnlyList <IDatabaseColumn> > LoadColumnsAsyncCore(Identifier tableName, CancellationToken cancellationToken)
{
var query = await DbConnection.QueryAsync <ColumnDataV10>(
ColumnsQuery,
new { SchemaName = tableName.Schema, TableName = tableName.LocalName },
cancellationToken
).ConfigureAwait(false);
var result = new List <IDatabaseColumn>();
foreach (var row in query)
{
var typeMetadata = new ColumnTypeMetadata
{
TypeName = Identifier.CreateQualifiedIdentifier(Constants.PgCatalog, row.data_type),
Collation = !row.collation_name.IsNullOrWhiteSpace()
? Option <Identifier> .Some(Identifier.CreateQualifiedIdentifier(row.collation_catalog, row.collation_schema, row.collation_name))
: Option <Identifier> .None,
MaxLength = row.character_maximum_length > 0
? row.character_maximum_length
: CreatePrecisionFromBase(row.numeric_precision, row.numeric_precision_radix),
NumericPrecision = row.numeric_precision_radix > 0
? Option <INumericPrecision> .Some(CreatePrecisionWithScaleFromBase(row.numeric_precision, row.numeric_scale, row.numeric_precision_radix))
: Option <INumericPrecision> .None
};
var columnType = TypeProvider.CreateColumnType(typeMetadata);
var columnName = Identifier.CreateQualifiedIdentifier(row.column_name);
var isAutoIncrement = row.is_identity == Constants.Yes;
var autoIncrement = isAutoIncrement &&
decimal.TryParse(row.identity_start, out var seqStart) &&
decimal.TryParse(row.identity_increment, out var seqIncr)
? Option <IAutoIncrement> .Some(new AutoIncrement(seqStart, seqIncr))
: Option <IAutoIncrement> .None;
var isSerialAutoIncrement = !isAutoIncrement && !row.serial_sequence_schema_name.IsNullOrWhiteSpace() && !row.serial_sequence_local_name.IsNullOrWhiteSpace();
if (isSerialAutoIncrement)
{
autoIncrement = Option <IAutoIncrement> .Some(new AutoIncrement(1, 1));
}
var defaultValue = !row.column_default.IsNullOrWhiteSpace()
? Option <string> .Some(row.column_default)
: Option <string> .None;
var isNullable = row.is_nullable == Constants.Yes;
var column = new DatabaseColumn(columnName, columnType, isNullable, defaultValue, autoIncrement);
result.Add(column);
}
return(result);
}
